Authentication may be used to grant or deny access to a wide variety of systems such as, for example, web site servers, handheld devices and shared terminals (e.g., automated teller machines/ATMs, kiosks). While conventional authentication solutions may be suitable under certain circumstances, there remains considerable room for improvement. For example, touch screen authentication may involve physical interaction between the user and a touch sensitive display of the system during the authentication process, wherein the user may have difficulty remembering and/or entering passwords, personal identification numbers (PINs) and/or user identifiers (IDs). Additionally, air gesture authentication may involve the use of peripheral cameras to capture video footage of hand gestures made by the user. In such an approach, relatively expensive cameras that draw significant amounts of power may use a relatively large amount of storage space to record and process the video footage. In another approach, a separate device may be used to capture motion input from the user, wherein the separate device may be powered throughout the authentication process. In addition to the increased power consumption of such an approach, the separate device may be cumbersome to hold/manipulate.